Valve unit



Feb. 18, 1958 G. N. cHATHAM ETAL 2,823,691

VALVE UNIT 8 Filed Deo. 13, 1955 United States Patent O VALVE UNIT George N. Chatham and O Shurtlelf, Austin, Tex. Application December 13, 1955, Serial No. 552,863

9 Claims. (Cl. 137-119) This invention relates to valves, and more particularly to those suitable for use when a reversing valve is needed, such as in reverse cycle refrigeration systems.

In a reverse cycle refrigeration system, defrosting of the evaporator or freezing unit is accomplished by delivering hot compressed refrigerant gas directly to the evaporator. This is done by reversing part of the ilow in the system by means of a valve unit, which heretofore has allowed the sudden surge of compressed gas from the condenser at the moment of reversal to impact against the compressor. Also such valve units have been rather complicated and expensive, because the dilerent movable elements therein have been linked together mechanically, thereby requiring a considerable degree of accuracy in making the valves. Also, in the past, the alternate reversing and return of the system to normal llow has had to be done either manually or by timing devices.

It is among the objects of this invention to provide a multiple outlet valve unit which may be operated automatically without the use of external timing devices, which can readily be controlled with a small amount of energy, in which the movable elements follow the path of least resistance to lluid llow, in which the different movable elements are not physically connected with one another in any way, in which the movable elements seat fully and gently in all positions, and which when used as a reversing valve in a pressurized system will permit surge pressure to be dissipated at points of lowest pressure in the system without first passing through the `compressor or pump.

The invention is illustrated in the accompanying drawings, in which i Fig. l is a central longitudinal section through a threeway `valve unit; and

Fig. 2 is a similar section through a four-way valve unit forming part of a reverse cycle refrigeration system.

Referring to Fig. l of the drawings, a valve housing 1 is provided with an inlet 2 and two outlets 3 and 4. The inlet opens into the upper part of a verticalpassage 6, the opposite side of which has upper and lower outlet ports. The upper port 7 opens into the side of an upper chamber and the lower port 8 opens into the side of the lower part of a lower chamber. The two chambers are separated by a partition block 9, which has a passage 10 through it connecting the upper chamber with the upper outlet 3 of the valve housing. Around the upper end of this passage, the block forms a seat for the tapered lower part of a control valve 11 that can slide up and down in the upper chamber. The control valve preferably is provided with a central vertical passage 12 through it. When the valve is on the seat, the upper end of this passage is closed by a closure pin 13 `on the lower end of the core 14 of a solenoid coil 16. The coil encircles a vertical .tube 17 mounted on top of the valve housing and having a closed upper end. The solenoid core is raised in this tube when the coil is energized, as shown.

2,823,691 Patented Feb. 18, 1958 ICC Slidable vertically in the lower chamber of the housing is a floating valve 21, by which is meant a valve that is actuated only by lluid pressure, gravity or spring pressure. Its lower part is tapered downward and normally closes the upper end of a passage 22 that connects the lower chamber with the lower outlet 4 of the valve. The bottom of the block 9 above this valve` has a small opening 23 through it connecting the upper and lower chambers. The top of the lloating valve preferably carries a gasket 24, which engages the bottom of the block when the valve is raised.

When this valve unit is not in use, both the control valve 11 and the iloating valve 21 will be in their lower positions, where they are held by gravity, and closure pin 13 will be resting on top of the control valve. As soon as lluid under pressure is delivered to the inlet 2 of the valve housing, it will raise the lloating valve to its dotted line position because the space above it is connected by the Small opening 23 with the lower pressure at the upper outlet 3. With the floating valve raised, flow is through the main passage 22 connecting port 8 with the lower outlet 4.

When it is desired to shut olf the lower outlet and open the upper one, the solenoid is energized, which causes its core and closure pin to rise. As soon as the pin leaves the top of the control valve, the space above that valve is connected through its central passage 12 with the lower pressure at the upper outlet. This, in combination with the pressure in the upper chamber around the bottom of the control valve, causes it to rise to the top of the chamber as shown and to open the alternate main passage 10 between the port 7 and the upper outlet 3. At the same time, the lluid pressure on top of lloating valve 21 is equalized with that below it, because opening 23 connects the upper chamber with the lower chamber above that valve. The floating valve therefore will descend by gravity and close the main passage between the inlet and the lower outlet. The rate of descent of the lloating valve can be controlled by the size of opening 23.

As soon as the solenoid is deenergized, its core and closure pin will drop and close the passage through the control valve. The weight of this unit will cause it to descend, because the iluid from the housing inlet will leak up around the control valve and equalize the pressure at its top and bottom. When the control valve reaches block 9 and closes the `alternate main passage 1t), the iluid pressure from the inlet will again force the iloating valve to rise and open the main passage 22.

It will be seen that this valve can be controlled very simply by merely raising and lowering the pin 13 that closes the passage through control valve 11. Fluid pressure in the valve housing or gravity then causes the control valve and iloating valve to move to their proper positions. As there are no mechanical connections between the control valve and the floating valve, there is nothing to get out of adjustment, and construction of the valve unit is greatly simplified. Of course, the control valve ycan be raised and lowered in many otherl to assist gravity or even to take its place if the valves moved horizontally instead of vertically. ThisV insures quiet and gentle closing of the valves with little effort. Nevertheless, once the valves reach their seats, the pressure dillerential between their tops and bottoms immediately increases materially and the valves are held on their seats tightly by uid pressure. The valves always move in the direction of least resistance.

A three-way valve unit of the type just described can be converted into a fourwvay reversing valve unit by adding to it another oating valve and another outlet. Such a valve unit is shown in Fig. 2. In the particular one illustrated, the valve housing 26is taller than before, and the lower part of the verticalpassage 27 along one side is provided. with a pair of vertically spaced ports 28 and 2-9. These ports open into two different chambers 30 and 31, which are separated by a partition block 32. The block is providedv with a passage 33 through it, the upper end of which normally is closed` by the tapered lower part of a control valve 34 that can move up and down in the upper chamber. Like the control valve previously described, this one may have a central vertical passage 36 through it which normally is closed by a closurepin 37 resting on the top of the valve.

Slidable vertically in the lower chamber is a main floating valve 38, the tapered lower end of which normally closes the upper end of a passage 39 at the bottom of the chamber. The two chambers 30 and 31 are in communication with each other at certain times through a small opening 41 in the bottom of partition block 32. This opening is closed by the iloating valve when it is in its upper position, the top of the valve preferably carrying. a gasket 42 that engages the bottom of the block around the opening.

The outlets from the two chambers open into the upper and lower portions of ay vertically extending chamber 44, with which the valve housing is provided at the side opposite to passage 27. This chamber is connected with the, outside of the valve unit by three vertically spaced ports 45, 46 and 47 designed for connection in a lluid circulating system. Chamber 44 also contains a secondary floating valve 48, which has opposed upper and lower valve members 49 and 50 rigidly connected by a vertical stem 51 that is considerably smaller than the smallest part of the chamber. A piston 52 is mounted on the lower part of this valve belowthe lower valve member. The central portion of chamber 44 is reduced in diameter in order to provide valve seats 53 and 54 above and below the middle port 46, which always serves as an outlet from the housing. When the floating valve is in its lower position, shown in dotted lines, its upper valve member 49 rests on the upper seat 53, and the lower valve member 50 is located below the lower port 47, but passage 39 remains in communication with chamber 44 below piston 52. The middle land lower ports are connected through the chamber around the valve stem. When fluid pressure is admittedV to the lower end of the chamber below the valve piston, the secondary floating valve is forced upward until its lower valve member 50 engages the lower seat 54. This places the upper port 45 in communication with the middle port. As will be shown presently, the upper and lower ports alternate as inlets and outlets.

The control valve 34 may be raised in the same manner as shown in Fig. 1 or in some other way. When this reversing valve unit is used in a reverse cycle refrigeration system, it is preferred to operate the control valve automatically in the manner shown in Fig. 2. It will be observed that closure pin 37 -is Slidable vertically in a vertical bore 56 in the valve housing above the control valve. Also Slidable in this bore is the enlarged lower end of a piston rod 57, the upper end of which extends up out of the bore and is connected to the bottom of a` piston 58 in a cylinder 59, with which the top of thevalve housing is provided. When the piston is in its lower dotted line position, it rests on the bottom of the cylinder beneath an outlet port 61, which connects the side f: the cylinder with the upper part of housing passage 27'. An inlet port 62 to the cylinder is formed inther opposite side of the housing and extendsV into a recess 63 below the piston. In a refrigeration system this inlet port is connected by a pipe 64 with the outlet of the compressor 65.

When compressed gas from the compressor is delivered to the inlet of cylinder 59, it forces the piston towards the top of the cylinder and thereby raises the stem 57 in the bore 56. The sudden rising of the enlarged lower end of the stem creates a partial'vacuum in the bore and thereby draws closure pin 37 up into the bore. As soon as passage 36 through the control valve is opened, the space above it is connected with the lower pressure in the upper part of chamber 44 above the secondary floating valve 48, which at that time is in its lower position. The compressed gasaround the lower part of the control valve forces it up to the top of upper chamber 30. At this time the main floating valve also is in its lower position, so flow of compressed gas is through port 28 and the alternate main passage 33 to upper port 45. Due to a loose fit of closure pin 37 inthe housingxbore, the pin slowly descends andi closes the upper end of the passage through control valve. 34. As soon as this happens, the fluid pressure above and below that valvel can equalize, and the valve will` descend by gravity until it reaches its Seat;

With the control valve closed and the top of lower chamber 31Y connected by openingk 41 with the lower pressure `at port- 45, the compressed gas in the lower part of the lower chamber forces main oating valve 38 to rise andy admit gas through main passage 39 to chamber 44 below the` secondary floating Valve. The pressure will raise the secondary valve until lits lower valve member S0 engages its seat 54 `as shown in full lines,v and the flow then will be through the main passage 39 from port 29 to the, lower port 47. The iiow is'frorn that port through a pipe 67 to the condenser 68, a pipe 69, theevaporator 70,` back through av pipe 71- to upper port 45 and out through; middle port 46- through pipe 72 to the inlet of the compressor; Refrigeration will take place as long as the ow is in this direction.

When enoughl cold has been produced, the compressor will stop and the control piston58 will descend in its cylinder. The seconda-ry floating valve 48 likewise will drop to its lower position. When the system calls for cold again, the compressor will start operating and that will raise the control piston, resulting as explained before in the rise of the. control valve `and ilow of hot compressed gas through upper chamber 30 and out through upper port 45 in reverse direction through the evaporator and condenser; and then in. through lower port 47 and out through the middle port to the compressor. This reversed ilow of hot gas will defrost the evaporator by the time the control valve descends and causes the valve unit to reverse sothat flow will be tmough its lower main passage 39 toV lower port 47. The length of the defrosting period is determined bythe rate of descent of closure pin, 37, and that dependson the tit ofthe pin in bore 56.

Thev control valve and mainY floating valve are operated' by fluidpressureand gravity inl exactly the same way as the corresponding` valves in Fig. 1. The secondary oating valve 48, which likewise is. free of any mechanical connections, also is: operatedY by fluid measure and gravity, although in all cases springs could be substituted for gravity if the valve unit is mounted horizontally instead of: vertically; The movements of the secondary floating valve alsoarey in the direction of least resistance and never against fluid pressure, but once seated, the valve is held rrnly against its seat by fluid pressure.

An important feature of this reversing valve unit when it is used` in a reverse cycle refrigeration system or similar fluid? pressure system, where there is a sudden backward pressure` surge through lower port 47 when controlvalve- 34 opensV alternate main passage 33 to rejversethefiow; is thatl the' surge is dissipated directly and ve'ry quickly tothe lowest' pressure point inA the system. In a refrigeration system that point is the evaporator.

The gas surge from the compressor enters the evaporator without rst having to go Vthrough the'compressor, which would restrict the surge and possibly be damagedby it.

The manner in which our valve unit connects the backward surge from the condenser to the evaporator is as follows. At the moment control valve 34 rises to reverse the valve, *the pressure surge entering the lower part of chamber 44 from the condenser will hold the floating valves 48 and 38 in their upper positions momentarily, and the compressed gas therefore will flow backward through main passage 39 and up through vertical passage 27 to port 28 and then through alternate main passage 33 and 45 to therevaporator. As soon as the surge` is dissipated in this manner and the pressure above and below main floating valve 38 is equalized, that valve will descend and shut off the main passage 39. This will be followed immediately by dropping of the other floating valve, whereupon the flow from the condenser will be connected with only the compressor through ports 47 and 46 until the valve unit is shifted back to normal flow operation.

A similar backward surge into chamber 44 exists through upper port 45 when the valve unit is restored to normal refrigerating duty. At that time, control valve 34 closes secondary passage 33, and the pressure in passage 27 raises the main floating valve 38 so that fluid pressure will be applied to the bottom of secondary oating valve 48. As the latter valve rises, port 4S will be connected through the central part of chamber 44 with port 47 briefly until valve member 50 engages seat 54. During that brief period, the compressed gas that formerly was leaving the valve housing through port 45 will be free to escape to the lowest pressure point in the system at that moment, the condenser, through port 47. The pressure surge is dissipated in this manner without being required to first go through the compressor. Consequently, regardless of whether the valve unit is being reversed or returned to normal operating condition, the surge pressure is released directly to the lowest pressure point in the system.

According to the provisions of the patent statutes we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

l. A valve unit for a fluid pressure line, comprising a housing having an inlet and main and alternate main flow passages communicating with the inlet, a control valve biased to close the alternate main passage, a floating valve for the main passage biased forward toward passage-closing position and movable backward by said line fluid pressure against the front surface of the floating valve to open it, means for causing said control valve to move and open said alternate main passage, and means for equaliziug the fluid pressure on the opposite ends of the floating valve when the alternate main passage is opened, whereby the floating valve will close the main passage. l

2. A valve unit for a fluid pressure line, comprising a housing having an inlet and main and alternate main flow passages communicating with the inlet, a control valve normally closing the alternate main passage, a floating valve normally closing the main passage and movable upwardly by said line fluid pressure beneath the floating valve to open it, the housing having an opening connecting the top of the floating valve with the alternate main passage at the downstream side of the control valve, and means for causing said control valve to move and open said alternate main passage, whereby the floating valve will descend and close the main passage.

3. A valve unit according to claim l, in which said control valve is movable upwardly by said line fluid pres- ""6 sure beneath it to open the alternate main passage and is provided with a` passage extending therethrough from top to bottom, a vertically movable closure member nor-Y mally resting on the control valve and closing the upper end of its passage, and means for reducing the fluid pressure above said closure member to cause it to rise and open said control valve passage, said member having a loose fit in said housing so that it will slowly descend and close the upper end of the control valve passage again.

4. A valve unit according to claim l, in which said control valve is movable upwardly by said line fluid priessure beneath it to open the alternate main passage and is provided with a passage `extending therethrough from top to bottom, a vertically movable closure member normally resting on the control valve and closing the upper end of its passage, said housing having a vertical bore in which the closure member slides and a chamber above the bore, a piston in said chamber normally at the bottom thereof, and a `stem secured to the bottom of the piston and extending down into said bore, 1said inlet communi-` cating withA the bottom of said chamber, and the inlet` ends of said main and alternate main passages communieating with that chamber above the lowered piston, whereby when pressure fluid is delivered to said inlet the piston will be raised in its chamber to connect the inlet with said main and alternate main passages and to reduce the fluid pressure in said bore so that said closure member will rise and open said control valve passage, said member having a loose fit in said bore so that it will slowly descend and close the upper end of said control valve passage.

5. A four-way valve unit for a fluid pressure line, comprising a housing having an inlet and a row of three laterally spaced ports for fluid flow, the housing also having a chamber connecting the inner ends of all three ports together and provided with valve seats between the middle port and the outer ports, a main passage connecting said inlet with one end of the chamber, and an alternate main passage connecting the inlet with the other end of the chamber, a control valve normally closing the alternate main passage, a main floating valve for the main passage biased forward toward passage-closing position and movable backward by said line fluid pressure against the front surface of the floating valve to open it, a secondary floating valve in said chamber biased in one direction to close it between the middle port and one of the outer ports and movable in the opposite direction by fluid pressure in the main passage to cut off communication between the middle port and the other outer port, means for causing said control valve to move and open said alternate main passage, and means for increasing the fluid pressure against the back of the main floating valve when the alternate main passage is opened, whereby to move the main floating valve forward into said main passage-closing position.

6. A four-way valve unit according to claim 5, in which the secondary floating valve has valve members spaced apart axially farther than said seats, whereby when either of said valve members engages its seat the other valve member will be spaced from its seat.

7. A four-way valve unit for a fluid pressure line, comprising a housing having an inlet and a row of three laterally spaced ports, the housing also having a chamber connecting the inner ends of all three ports together and provided with valve seats between the middle port and the outer ports, a main passage connecting said inlet with one end of the chamber, and an alternate main passage c011- necting the inlet with the other end of the chamber, a control valve normally closing the alternate main passage, a main floating valve for the main passage biased forward toward passage-closing position and having a front surface exposed to said line fluid pressure for opening the floating valve, a secondary floating valve in said chamber normally closing it between the middle port and the outer port at said other end of the chamber, the secondary valve neat-Leer` being movableby fluidy pressure todos@ Sadhambe between, themiddle port. andthe other Outer. perf when themainoating valve opens the main passagez means for causing saidcontrol valve to move and open said alternate main passage, and means for increasing the fluid pressure against the b ack of the main floating valve when theraltvernate mainvpassage ispopened, whereby to mov/e` the main floating valve forwardinto said main passage-closing position so that the secondary valve will return toits normal position.

8. A fourfway valve unitpfor a fluid pressure line, comprising a housinghaving an vinlet and `three vertically spaced ports for flow of fluid, the housing also having a vertically extending chamber connecting the inner ends of all three portsytogether and provided with valve seats between the middle port andthe upperand lower` ports, a main passage connecting said inlet with, the lower part of said chamber, andan alternatemain passageconnecting thepinlet with the upper partvof the chamber, a; controlvalve normally closingthe alternate mainpassage and movable upwardly to open, it, a main oating valve normally closing the main passage and movable upwardly by said line uid pressure 8 beneath it toropenit,A the housing having an opening 4conmeeting thetop of themain valve with the alternate main passage at the'downstreaim sideof the'control `valve,'a`

secondaryfiloating valve` in` saidA chamber vhaving vertically spaced seats `facing each other with theeupprer seat normal.- ly closingsthat chamber between the upper and middle ports, the secondary/'valve being movableupwardlybyr lluid pressure below it to close the chamber between the passage and ythe secondary valve will drop to its lowerl position.

9. A four-way Valve unit according to claim 8, in which said middle port is an outletY only andzsaidupper andv lower ports are combined inletseand outlets.

References Cited in the file of thispatent UNITED STATES PATENTS( 668,202 Netaefy Feb., 19, 1901 

